Where is the fuel pump shut off switch for a 1992 Ford E350 located?

There isn't a readily accessible, easily located fuel pump shut-off switch on a 1992 Ford E350 like you might find in some other vehicles. Ford didn't typically include these as standard equipment in that era. To shut off the fuel supply, you'd need to disconnect the fuel pump's electrical connection or deal with the fuel pump relay. Both options require some mechanical knowledge and potentially getting under the vehicle.

To find the fuel pump relay: Consult your owner's manual (if you have it) or a repair manual specific to your 1992 Ford E350. The relay is usually located in the underhood fuse box or, sometimes, in a separate relay center. Pulling the relay will stop the fuel pump from working. Remember to re-insert the relay once the issue is resolved.

To disconnect the fuel pump's electrical connection: This requires locating the fuel pump (usually in the fuel tank) and disconnecting the wiring harness. This is a more involved process and should only be attempted if you're comfortable working with automotive electrical systems. It is also important to follow appropriate safety measures to avoid fuel leaks and fire hazards.

Warning: Disconnecting the fuel pump should only be done for emergency shut-off situations or if working on the fuel system. Incorrectly disconnecting or reconnecting the fuel pump wiring can lead to safety hazards. If you are not comfortable performing these tasks, it's best to consult a qualified mechanic.